Effect of Striped Cucumber Beetle (Coleoptera: Chrysomelidae) Foliar Feeding on Pumpkin Yield

Field and laboratory studies were conducted to examine the relationship between foliar feeding damage caused by striped cucumber beetle, Acalymma vittatum (F.) (Coleoptera: Chrysomelidae), and yield of pumpkin, Cucurbita pepo L. (var. Spookie). In field trials in 1996 and 1997, plants were artificially infested with varying numbers of beetles at the cotyledon-, first-, second-, or third-leaf stages. At harvest, fruit number, fruit mass, and fruit maturity were evaluated. Foliar feeding damage had little effect on yield other than a slight increase in number of fruit per plant for plants with 1 to 20% damage. The stage of plant development at infestation had no effect on yield, nor did the interaction of foliar feeding damage and growth stage. In a laboratory trial, varying numbers of A. vittatum were allowed to feed for 1, 2, 3, or 4 d on plants at cotyledon-, first-, second-, or third-leaf stages. For all stages, significant and differing positive linear relationships were observed when the percentage of foliar feeding damage was regressed against beetle-days. The results indicated that small fruited, vining pumpkins can tolerate relatively high levels of striped cucumber beetle feeding injury. Foliar feeding damage thresholds are conservatively estimated to be ~60% during cotyledon through third leaf stage of growth.